A standardization organization 3GPP (The 3rd Generation Partnership Project) performs standardization of an LTE-Advanced (Long Term Evolution Advanced: LTE-A) mode as a communication standard of the next generation compatible with an LTE (Long term Evolution) mode. In the LTE-A mode, a wireless communication device (NE: Network Entity) of a network (E-UTRAN: Evolved Universal Terrestrial Radio Access Network) provides one or more communication cells (Hereinafter, simply referred to as cell). The wireless communication device is a device which is an access point of a wireless communication terminal (UE: User Equipment), such as, a base station (ENB: E-UTRAN Node B), a relay device (RN: Relay Node), or a repeater. The wireless communication terminal is included in one of the cells that the wireless communication device provides, and communicates with the wireless communication device of the cell that its own station is included. Hereinafter, the wireless communication terminal is simply referred to as “terminal”.
Introduction a CoMP (Coordinated Multiple-point Transmission/reception) technology in which a plurality of wireless communication devices perform multipoint coordination for one terminal and transmit wireless signals to the terminal into the LTE-A mode is reviewed. Characteristics of reception of a signal for the terminal can be increased by using the CoMP technology.
For example, the plurality of wireless communication devices which are used for the CoMP technology are respectively base stations (ENB) which can operate independently. One base station operates as a master base station performing concentrative control, and remaining base stations operate according to instruction of the master base station as a slave base station.
An IP (Internet Protocol) line which is called an X2 interface defined by 3GPP is connected between a mater base station and a slave base station. In a case where the CoMP technology is applied to a system of the known LTE mode, a system which cheaply uses the CoMP technology by using a public IP network can be introduced by using the X2 interface.
One of the CoMP technologies is a JT (Joint Transmission) mode. In the JT mode, a master base station transmits information necessary for performing coordinated transmission, such as, user data, transmission timing information, or a CQI (Channel Quality Indicator) to a slave base station through the X2 interface. A slave base station transmits the same user data in the same coding rate/modulation mode at the same timing as the master base station by using the same wireless resource. For this reason, a terminal can increase received power by synthesizing electric wave transmitted from a plurality of wireless communication devices, that is, the master base station and the slave base station.
One of modes different from the JT mode of the CoMP technology is a Blanking mode. In the Blanking mode, when the master base station transmits data by using predetermined wireless resource, the slave base station does not transmit (Muting) the user data by using the wireless resource. Thereby, interference power of the master base station decreases.
In the Blanking mode, the master base station transmits only the wireless resource which transmits data to the slave base station through the X2 interface, and does not transmit the user data, the transmission timing information, and the CQI. For this reason, it is possible to prevent traffic between base stations from increasing.